Draft regulator for combustion apparatus



L. MONNEY RAFT REGULATOR FOR COMBUSTION APPARATUS Filed Jan. 7, 1938 July 25, 1939.

V the flue.

' Patented July 25, 1939 UNITED STATES DRAFT REGULATOR FOR COMBUSTION V APPARATUS Louis Monney, Lausanne, Switzerland, assigno' to the firm Recomatic S.-A., Genova, land, a, firm of Switzerland Switzer- Application'January '7, 1938, Serial No. 183379 In Switzerland November 15, 1937 4 Claims.`

This invention relates to draft regulators for combustion apparatus of the type in which a fiue gas Conduit is provided With an opening for admitting air into the flue.

It is an object of the invention to provide a simple and reliable' thermostatically actuated shutter device for controlling the admission of air through'the opening in the flue in accordance with the temperature of the gases passing through A further object of the invention is the provision of a manually operable adjust-.ing device for'varying the rate of movement of the shutter under the action of a thermostat, so as to increase or decrease the admission of air in the flue'independently of the thermostat when the rate of combustion is desired to be changed.

N These and other objects will be apparent from the following description when considered in connection with the accompanying drawing in which,

Figure 1 is an axial Vertical section of a preferred' form of draft regulator according to the invention, as applied to` a flue'gas Conduit or chimney of afurnace for domestic heating purposes.

Figure 2 is a plan View of a detail part of the device.

Figure 3 is a vertical section showing the shutter in closed position.

A flue gas conduit or chimney l of afurnace, not shown, is provided with a lateral opening 2. A frame 3 is fixed to the wall of the chimney I along the edges of the opening 2 and. projects forwardly of the opening. The frame 3 is pro- Vided with an opening 4 within which is mounted a Shutter 5 capable of tilting about lateral journals 6 the axis of which passes approximately through the center of gravity of the Shutter' 5. A support 'I is secured to the frame 3 and carries sa wire netting 8 which coVers the entire opening 4 to protect the Shutter 5' against being touched. The upper part of the support 'I is provided with a vertical slot 9. The Shutter 5 is 'provided with a slot IO which, when the Shutter is closed, extends parallel to the slot 9.

On both sides of the slot o, the shutter 5 carries a bracket ll provided. with a circularly curved slot !2 extending parallel to the slot ll] of the Shutter. Two slotted guide bars l3, carried by a sliding bolt !4 traverse the slot o of the Shutter and pass between the two brackets ll. The bolt |4 can be locked by a nut l5 at difierent positions along the slot 9. The guide bars l3 are so directed that in any position of the Shutter 5 and of the slide M they intersect the slots !2 of the brackets ll. A rod |6 has one endenaged in a sleeve ll, while its other'end carries a pin l8 which penetrates through all four slots 12 and l3. A second rod l9 is also engaged in p, the sleeve I'I. and a clamping screw 20 locks the two rods IE and s inthe sleeve l'l which permits to vary the total length of the two rods. The rod !9 is rotatably connectedto one end of a flat blade 2| of heat responsive material, the u curvature of which depends on the temperature in the chimney l. The other end of the ;blade 2l is fixed to an arm 22- carried by the frame 3-. I

The bimetallic blade ZI isso disposed 'thatits end connected to the rod l9-is bent towards the W right hand side in Figure l when the temperature 1'5 rises, so that the effect of such bendng is to open the shutter 5 to the represented inelinedposition. Exterior air is then admitted through theopening 4 and the wire netting 8 with theefiect of` decreasing the draught in the chimney, so that less air is drawn in through the grate of the fur nace. Accordingly, the rate of combustion de creases and the temperature in the chimneyfall's, so that the blade 2l straightens itself, 'the upper end thereof moving towards the leftand lo ses the Shutter 5. When the Shutter is in closed position, its lower end bears against a transversally extending abutment 23. In order to avoid a flexion of the blade 2l when, in closed position of the Shutter, the slide l4 is moved along the slot 9, the circularly curved slots l2 of the brackets ll have their center of curvature Situated on the axis 24 of the rotatable connection between the blade 2| and the rod l9. Thus, upon displacement of the slide !2 carrying the guide bars 13, the blade 2l remains immobile, while the rods 16 and l9 simply turn about the axis 24. It will be recognised that when the slide !4 is fixed at a higher position than that represented in Figure 1, the Shutter 5 will open less far for the same curvature of the blade ZI, while when moving the slide l4 further downwards, the Shutter will open more for the same curvature of the blade 2| than in the represented position. The journals 6 of the Shutter are so disposed that the shutter is substantially balanced or has a slight tendency to turn in the direction of its opening movement. In this latter case a portion of the excess weight of the upper part of the Shutter is supported by the guide bars !3, 50 and the flexion of the blade ZI will practically not be influenced by the weight of the Shutter, so that the temperature of the flue gases alone will determine the amount of flexion of the blade, ju

and the effect of the inertia of the moving shutter can be neglected, since the variations of the rate of combustion and accordingly the variations of the temperature and the movements of the shutter are slow.

A screw 25 is screwed into the frame 'l and serves to lock the shutter 5 in closed position, for example during the transport or during mounting of the shutter, in order to prevent any movement of 'the shutter which could deteriorate the bimetallic blade ZI. The shape of the guide bars |3 could be otherwise than represented in the drawing, for example they could extend in horizontal direction or be more inclined than those shown. The direction of these guide bars also determines the amount of opening of the shutter for any given curvature of blade 2l.

I claim:

1. In combination with the fine of a combustion apparatus having an opening for admitting air, a pivotally mounted shutter for ccntrolling the admission o air through said opening, a thermostatsubjected to the temperature of the gases passing through the flue, a slotted member carried by the shutter, a rod having cne end connected to the thermostat and the other end engaging the slot in said member, and manually operable means for moving the slot engaging end of said rod along said slot to vary the rate of movement of said shutter under the action of the thermostat.

2. In combination with the fiue of a combustion apparatus having an opening for admitting air, a pivotally mounted shutter or controlling the admission of air through said opening, a thermostat subjected to the temperature of the gases passing through the flue, a slotted member carried by the shutter, a rod having one end connected to the thermostat and the other end engaging said slotted member of the shutter, a fixed guide member exteriorly of said ;opening in the flue, and manually operable means movable along said guide member for moving the end of said rod engaging said slotted member along the slot therein to vary the rate of movement of the shutter under the action of the thermostat.

3. In combination with the ue of a combustion apparatus having an opening for admitting air, a pivotally mounted shutter for controlling the admssion of air through said opening, a thermostatic blade subjected to the temperature of the gases passing through the fiue, a bracket carried by said shutter and provided with a circularly curved slot, a rod having one end rotatably connected to said thermostatic blade and the other end engaged in said slot of the bracket carried by the shutter, a fixed guide member exteriorly of said opening in the flue, and manually -operable means movable along said guide member and o peratively connected to the end of said rod engaging said curved slot for moving said end along the slot to vary the rate of movement of the shutter under the action of the thermostatic blade the center of curvature of said slot, when the shutter is in closed position and the thermostatic blade not subjected to heat, being Situated on the axis of the rotatable connection between said rod and the blade.

,4. In combination with the flue of a combustion apparatus having an opening for admitting air, a pivotally mounted shutter for oontrolling the admission of air through said opening, a thermostatic blade disposed within the fiue, a slotted member carried by the shutter, a rod having cne end rotatably connected to the thermostatic blade and the other end engaging said slotted member, a fixed guide member exteriorly of said opening in the fiue, a manually operable slide movable along said guide member, and a slotted arm carried by the slide and engaging the end of said rod engaged in said slotted member of the shutter, whereby upon moving said slide along said fixed guide member said end of the rod being moved relative to said slotted member to vary the rate of movement of the shutter under the action of the thermostatic blade.

LOUIS MONNEY. 

